Description
Fully-automatic naval gun mount employed against surface (Anti-Surface Warfare - ASuW), air (Anti-Air Warfare - AAW) and land attack (Naval Surface Fire Support - NSFS) targets.

Background
The MK 45 gun was developed as a lighter weight, more easily maintained replacement for the MK 42 5"/54 caliber gun mount. It is designed to engage surface and air targets and to provide naval surface fire support for expeditionary operations. The MK 45 MOD 4 gun mount upgrade includes a longer barrel (62 caliber) that improves the gun's effectiveness as a land attack weapon (naval surface fire support).

The gun mount includes a 20 round automatic loader drum. The gun's maximum firing rate is 16-20 rounds from the loader drum per minute. The rounds in the loader drum can be fired with one crewmember located at the EP-2 console below deck. Additional rounds can be loaded and fired by the full crew (Mount Captain, EP-2 Operator and four ammunition handlers), all of which are stationed below deck.

The MK 45 gun is installed aboard DDG 51 and CG 47 class ships.  

General Characteristics Primary Function: Fully-automatic, naval gun mount.
Date Deployed: 1971 (Mark 45 Mod 0)
Range: 13 nautical miles (14.9 statute miles) with conventional ammunition.
Type Fire: 16-20 rounds per minute automatic, conventional ammunition.
Magazine Capacity: 600 rounds conventional for Destroyers; 1200 rounds conventional for Cruisers.
Caliber: 5 inch 54 caliber (MK 54 Mod 1/2) barrel length of 270 inches (54 x 5)
Guidance System: MK 45 Gun Mount is remotely fired from the MK 160 Gun Computer System or MK 86 Gun Fire Control System during normal operations
Platforms: MK 45 MOD 1 (5"/54) - CGs 61, 65-68 (2 gun mounts per ship). MK 45 MOD 2 (5"/54) - DDGs 51-80 5" 54 (1 gun mount per ship); CGs 69-73 (2 gun mounts per ship). MK 45 MOD 4 (5"/62) - DDG 81-113AF (1 gun mount per ship); CG 52-60, 62-64 (2 gun mounts per ship).